Analyzing Forensic Evidence Based on Density with Magnetic Levitation

• NCJ Number: 243725
• Journal: Journal of Forensic Sciences Volume: 58 Issue: 1 Dated: January 2013 Pages: 40-45
• Author(s): Matthew R. Lockett, Ph.D.; Katherine A. Mirica, Ph.D.; Charles R. Mace, Ph.D.; Robert D. Blackledge, M.S.; George M. Whitesides, Ph.D.
• Date Published: January 2013
• Length: 6 pages
• Publication Format: Article
• Publication Type: Report (Technical)
• Language: English
• Country: United States of America

Annotation

This paper describes a method for determining the density of contact trace objects with magnetic levitation (MagLev).

Abstract

This paper describes a method for determining the density of contact trace objects with magnetic levitation (MagLev). MagLev measurements accurately determine the density (+/- 0.0002 g/cm3) of a diamagnetic object and are compatible with objects that are nonuniform in shape and size. The MagLev device (composed of two permanent magnets with like poles facing) and the method described provide a means of accurately determining the density of trace objects. This method is inexpensive, rapid, and verifiable and provides numerical valuesindependent of the specific apparatus or analystthat correspond to the absolute density of the sample that may be entered into a searchable database. Researchers discuss the feasibility of MagLev as a possible means of characterizing forensic-related evidence and demonstrate the ability of MagLev to (i) determine the density of samples of glitter and gunpowder, (ii) separate glitter particles of different densities, and (iii) determine the density of a glitter sample that was removed from a complex sample matrix. Abstract published by arrangement with John Wiley & Sons.